Then he went back and slew a male goat, which likewise must be without defect, and did the same thing with its blood.
This was known as the atonement sacrifice.

(See Leviticus 16:1-34) It was an offering for sin, made for the people of Israel, but in fact foreshadowing the great sin-offering that is to take away the sin of the world.
[195]St.Paul plainly tells us that the things here done foreshadowed better things to come.

(Hebrews 10:1) God required in the law that the Jews should keep this day of atonement and offer these sacrifices through the high priest once each year.

We remember that God had promised to Abraham: "In thy seed shall all the families of the earth be blessed".

So St.Paul says that the law "was added because of transgressions, till the seed should come to whom the promise was made; and it was ordained by angels in the hand of a mediator"; and that the law was a schoolmaster to bring the people unto Christ.